Creating hybrid nanostructures consisting of disparate nanoscale blocks is of interest for exploring new types of quantum device architectures. Here, we demonstrate the novel anchoring of gold nanoparticles of ~13 nm diameter to sidewalls and ends of carbon nanotubes (CNTs) via covalent interactions between methyl mercaptoacetate capping the nanoparticles and amine-terminated CNT surfaces. Ethylenediamine was grafted onto the surface of the nanotubes by covalent interaction between amine groups and the chlorocarbonyl groups on the carbon nanotube surface to give amine-functionalized CNTs. Mercaptoacetate capped 13 nm gold nanoparticles were subsequently anchored to the surface of the nanotubes through the covalent interaction between nanotubes and the nanoparticles. Novel nanoassemblies of carbon nanotubes (CNT) and gold nanoparticles were obtained. These assemblies were confirmed by UV-visible, transmission electron microscopy, FTIR, and X-ray powder diffraction methods. This approach provides an efficient method to attach other nanostructures to carbon nanotubes and can be used as an illustrative detection of the functional groups on carbon nanotube surfaces. Such molecularly interlinked hybrid nanoblocks are attractive for building biocompatible nanodevices.